Make no little plans; they have no magic to stir men's blood and probably themselves will not be realized. Make big plans; aim high in hope and work, remembering that a noble, logical diagram once recorded will not die..." - Daniel Burnham (1911)
I devoted several months in privacy to the composition of a treatise on the mysteries of Three Dimensions. Only, with the view of evading the Law, if possible, I spoke not of a physical Dimension, but of a Thoughtland whence, in theory, a Figure could look down upon Flatland and see simultaneously the insides of all things, and where it was possible that there might be supposed to exist a Figure environed, as it were, with six Squares, and containing eight terminal Points. But in writing this book I found myself sadly hampered by the impossibility of drawing such diagrams as were necessary for my purpose...
Make no little plans; they have no magic to stir men's blood and probably themselves will not be realized. Make big plans; aim high in hope and work, remembering that a noble, logical diagram once recorded will not die, but long after we are gone be a living thing, asserting itself with ever-growing insistence...
Daniel Burnham quoted in: Charles Moore (1921) Daniel H. Burnham, Architect, Planner of Cities Boston, Houghton Mifflin. p. 19-21
How could one argue with a man who was always drawing lines and circles to explain the position; who, one day, drew a diagram [here Michael illustrated with pen and paper] saying 'take a point A, draw a straight line to point B, now three-fourths of the way up the line take a point C. The straight line AB is the road to the Republic; C is where we have got to along the road, we canot move any further along the straight road to our goal B; take a point out there, D [off the line AB]. Now if we bend the line a bit from C to D then we can bend it a little further, to another point E and if we can bend it to CE that will get us around Cathal Brugha which is what we want!' How could you talk to a man like that?
Michael Collins, referring to de Valera in conversation with Michael Hayes, at the debates over the Anglo-Irish Treaty in 1921
Schematic diagrams are more abstract than pictorial drawings, showing symbolic elements and their interconnection to make clear the configuration and/or operation of a system.
Ernest O. Doebelin (1995) Engineering experimentation: planning, execution, reporting. p. 451
A diagram is a graphic shorthand. Though it is an ideogram, it is not necessarily an abstraction. It is a representation of something in that it is not the thing itself. In this sense, it cannot help but be embodied. It can never be free of value or meaning, even when it attempts to express relationships of formation and their processes. At the same time, a diagram is neither a structure nor an abstraction of structure.
Peter Eisenman (2007) Written Into the Void: Selected Writings, 1990-2004. p. 88
Steve Mellor and I independently came up with a characterization of the three modes in which people use the UML: sketch, blueprint, and programming language. By far the most common of the three, at least to my biased eye, is UML as sketch. In this usage, developers use the UML to help communicate some aspects of a system. As with blueprints, you can use sketches in a forward-engineering or reverse-engineering direction. Forward engineering draws a UML diagram before you write code, while reverse engineering builds a UML diagram from existing code in order to help understand it.
Martin Fowler (2004) A Brief Guide to the Standard Object Modeling Language. p. 2
A diagram, indeed, so far as it has a general signification, is not a pure icon; but in the middle part of our reasonings we forget that abstractness in great measure, and the diagram is for us the very thing. - Charles Sanders Peirce, 1885
To show this diagram properly, I would really need a four dimensional screen. However, because of government cuts, we could manage to provide only a two dimensional screen.
Peirce (1932: 2.278) distinguishes two kinds of icons: pictures and diagrams, the latter of which he illustrates with the example of an electrical wiring diagram in relation to the wiring itself. But the difference between a picture and a diagram, as Peirce himself notes, is relative. The picture always abstracts from some features of the object it portrays, e.g., three-dimensionality in painting. The diagram is simply more abstract. The difference, then, is one of degree and not of kind.
Marge E. Landsberg (1995) Syntactic Iconicity and Linguistic Freezes: The Human Dimension . p. 58
I've had enough of breakdowns and diagrams — judging from picture books, apparently Heaven is a partly cloudy place.
Many different types of pictorial representations are used in instruction. On a scale of very concrete to very abstract, first comes the photograph. Next are true-to-life drawings which lose some detail compared to the photograph. Diagrams are more abstract, but generally depict recognizable objects and preserve spatial relationships. Lastly graphs and plots are completely abstract representations of sets of data.
Donald Peterson (1996) Forms of Representation: An Interdisciplinary Theme for Cognitive Science. p. 33
A diagram, indeed, so far as it has a general signification, is not a pure icon; but in the middle part of our reasonings we forget that abstractness in great measure, and the diagram is for us the very thing.
Charles Sanders Peirce (1885) "On The Algebra of Logic : A Contribution to the Philosophy of Notation" in The American Journal of Mathematics 7, p. 180-202
The government are very keen on amassing statistics. They collect them, add them, raise them to the nth power, take the cube root and prepare wonderful diagrams. But you must never forget that every one of these figures comes in the first instance from the chowty dar [chowkidar] (village watchman in India), who just puts down what he damn pleases.
One day I went alone to the river to enjoy myself as usual. When I was a short distance from the masonry, however, I was horrified to observe that the water had risen and was carrying me along swiftly.… The pressure against my chest was great and I was barely able to keep my head above the surface.… Slowly and gradually I became exhausted and unable to withstand the strain longer. Just as I was about to let go, to be dashed against the rocks below, I saw in a flash of light a familiar diagram illustrating the hydraulic principle that the pressure of a fluid in motion is proportionate to the area exposed and automatically I turned on my left side. As if by magic, the pressure was reduced.